Oxaziridines configuration determination

For oxaziridines the N-inversion barrier is considerably higher than that for similar aziridines. Af-Alkyl-3,3-dialkyloxaziridines are resolvable and absolute configurations have been determined (Section 5.08.2.3.1). 

Nitrogen chirality may also be produced by the action of an achiral peroxyacid on a Schiff base containing a chiral amine (75JOC3878). In this case the oxaziridine contains a configurationally known centre of chirality relative to this, absolute configurations of the centres of chirality at nitrogen and carbon, and thus the complete absolute configuration of the molecule, can be determined (see Section 5.08.2.2). 

More definitive studies were carried out of analogous reactions including x-ray analysis and, therefore, the absolute configurations of the new chiral centers in the resulting oxaziridines 30-33 were determined. 

The absolute configuration of an oxaziridine made from p-bromobenzyl-idene-a-S-phenylethylamine has been determined by X-ray analysis." ... 

Davis et al. used a chiral oxaziridine for the asymmetric oxidation of sulfides to sulfoxides.Oxidation of isopropyl- -tolyl sulfide (427) with oxaziridine 428, for example, gave 60.3% ee (S) of 429 (at -78°C in chloroform).5 0 The absolute configuration of the sulfide is determined by approach of the sulfide to the oxaziridine oxygen, as illustrated by 430. Steric factors appear to be the primarily reason for the chiral recognition. 5 1 In this model, attack by sulfur minimizes the Rl and Rs interactions with the oxaziridine... 

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